This invention relates to an intake system for internal combustion engines with two suction pipes of different lengths departing from a main intake pipe, which pipes can be connected individually, preferably in accordance with the engine speed, to the intake passage in the cylinder head leading to the intake valve, the main intake pipe being connected to each intake passage by a connecting piece, and the suction pipes of different lengths departing from the main intake pipe opening into this connecting piece in the direction of the axis of the connecting piece, or on opposite sides thereof, and a butterfly control valve being arranged in the connecting piece, which valve is positioned on a shaft parallel to the longitudinal axis of the engine, and which in two positions, i.e., its two extreme positions, establishes the flow connection between one of the suction pipes and the intake passage and disconnects the flow connection between the other suction pipe and the intake passage.